Sound re-recording system



Feb 8 1944- w. v. woLFE SOUND R13-RECORDING' SYSTEM Filed June 12, `1942 2 Sheets-Sheet l W'L/.Acs 17.' WL FE,

Etno.

ATTORNEY.

Feb. 8, 1944. w. v. woLFE SOUND RF1-RECORDING SYSTEM Filed June 12, 1942 2 Sheets-Sheet 2 p/fff'er v differ' Hm Re y WALLACE T/Z'WLFE,

INVENTOR. BY W/MM ATTORNEY.

Patented Feb. 8,

Malisse Wolrereveriv Vrissflrrror en 'Radio v Ik'rlvoririi. on' 'jor 'is horrors- This invention relates to `the rodillo-lion ef sound records -for potion `pioture ylmsland ticularly y1304;. re-reoording'system gin' ,which 9.112111- rality of sound records Vare coll'rilrai'nfe,d finto?. single composite sound IeQOrd, Athe volume of egon of yseid plurality 'of soifiiidireeords being `.uriner olontrol of one or more oo ntrolreoords.

In .the Produetion'of motion view/re sound ree.- ords, it is` customary to l re-record 'the Aolgirml Sounds 'on Lilie Se@ Combined Y. iiv'lh sound efreeo'ssuehhesierew thundersnnrnensrms o innosieesoun r for release eo westers. Mv recensies. L2 219:01@ of April f1, 21942, discloses end olsi rre-reeoril inssystemiof thistme lr slioli efsystem'wgherein a. control tone or reco 4 of i',he Aa.;11;`;1 itu `;ie Tigri .tions of eeen o f sound reeo'rcis seins re,- recorded 'lis Valso recorded or made du "s ref heersellend wliiehsiv iurrieontrolsrhe e-of the respective sonro reoords during *subsequent rehearsals and during the final IreV- recprding' 1n the re-reoordng of sound it is Vo f course de Vsirrible to prodiioe Tas .noiseless e eorrroosire sonne record vas possible. Theiusualsystenx jfor reQ- reeording employs .a fnonnsl" sound recorderr wherein Stenderd ,types of .noise reduction ere incorporated; However, a. marked improvement in noise reduction .isobtainedliy bovins .the noise reduction 'aerien' zeniioioete rire impression' of the Signal -noonelije 'f llin to @void Deskoliopins and Provide la desirsble margin.' and *suon SySf vreins have' 'Dreoll'sly browsed Forl inf sianoe;"Kel1ogg Psrenrolll .off Qotober 126 1,937, discloses en dntcpiory Qf I IOS@ fuucuon" re-recording 'system wherein tneyspund track ,beine refreeoir'dedis 'soeniied ettwo :bosrtions longitudinally 'of me one seqnning .op-

vtrie recorder endtlie'otlier oneretlon eonorolliirirv the Sismi recording" notion. suoli sistem beine- Ssiisretor hen s sinsie sound reeordlisbegrereoordednresenwiey'srsteinsfw. rein'esnrany f d ensound'r ordS 'roer be 'wily `fcollflbi-ned'into the' 'W26 Kellogg 'iraient' f or 'einen of the spo d "irh'presenft inveniion solves V iS bertifolrlli' edpfble t0 'the Eboli-WP# f re? recording 'system iiisiolosed in @lievementionen patent. inethgd'fof and systent pr Sound Heek of Lille dialogue .andthe in,

virerislri.te respective duction `@lotion Joy recording during e rehearsal a l'composit' `'sound record `eitheron or Von ein ieeefnied sc, heist r 'being' preferred, and -uti- -liz'i' vihiszreeor'dfor; onirfoliins the noise rediretion Portion of the reoorder dnrin'gf @the .iinsl Sound lake lirrililioli lthe amplitudes of the vfariijelzed when itis .oonsidered .phat the dialogue track ls .silent por-tions during times of'certgin sound effeots `"sind yice ver'spL. By using Acomposiige record of al1 signals the noise reduction Section lwiil `:nl iye's be .Present `for the signal being e prinoipal'lobject pf ythe present invention,

` thereforfe, is' piureiiryorsounol records.

mother obeet f the invention -iS .t0 mPrQve lthe M -recording .of e .plurlirr (olf sound reoordS btaxj 'anticipatory nisereducltion in the composite record. f A Iurtherobject o f the invention is to provide a. refreoordng system in which anticipatory noise `reduction is lobizzylned on the nal'record during there-regarding of 9. plurality of scund records.

`A fprtherobject Aof [the 'invention is provide a separate poise rednion 'Qontrol record for a plurality of refrecorded records Vto obtain anticiidtory' noise reduction on ,the composite record- 1 o lurslfs o fsondeprodneers s. 's sundrecords therein .to

eletrc'gl 'nrrents These 'reproduoers may be ro facilitate the ire-recording of s is also fed to an amplifier I9 and a loud and although only three are shown, it is to be understood ythat the system may operate with more than three units. The sound heads 5, 6 and 'I are connected to respective variable gain amplifiers 8, 9 and I0, the output thereof being fed into corresponding ampliers I3, I4 and I5. The output of the latter ampliers is combined and fed to a recorder I'I when the switch I 8 is closed. The output of ampliiiers I3, I4 and I5 speaker for monitoring purposes. i For controlling the volume of the 'signal currents from the sound heads 5, 6 and 1, a. mixing panel 22 is shown connected to the variable gain amplifiers 8, 9 and I0 and to a control tone source 23 and a control tone recorder and reproducer 24, the rectiers and other elements of which are shown in my above-mentioned Patent .No. 2,279,018. With the system just mentioned, the volume variations made to signalsin the respective transmission channels by manipulation of*` the potentiometers 26, 21 and 2B are recorded at 24 as 4a control toneliecord which, when reproduced, will repeat the volume variations made byl the niixer,"`t he mixexfstill. being able to vary the automatically Vcontrolled amplitudes, if desired. AConnectalle to the' ,output of .ampliiiers I 3, I andl fizhro'iigtr a switch' is .`a recordingiunit. which. is lshown 1iny the form of an y acetate disc recorded-although itl is Atobe understoodthat any'gsuitabletype of recorder may be used. Dur` ingarehefarsal-the switch 3l is closed and a compositeA record made of the combined sounds. When. the Aiirral. sound take fis'to be made, the switchl .is opened, and switch I8 closed and the record'rnade at 3Q is .reproduced by areproducing unit shown ,at 33 with a pickup' 52 and fed tothe noise reduction, elements of the re# corder I'Ithrough amplier rectifier unit 5I when". switch 32 is closed, the. acetate record being adev vanced ahead of the records iii-:ing reproduced4 to provide the anticipatory noise reduction aci-' tion. l Although s eparatevrecording andreproducing units 30 and 33` are illustrated, thesemay be combined into a single unit.

To illustrate the method of obtaining the noise reduction action, reference is made to Fig. 2,v wherein a standard type of sound recorder is represented to include a light source 35, the light, from which is collected Aby a lens 38 and ejected on a mask 3l having an aperture therein 'Ther emergent light through the aperture 38. andpas't noisereduction shutters 40 is projected ,by a lens 4I to lthe mirror of a galvanometer Q2 from which it is reflected to` aslitvmask I4 through a lens,

a -and b iohgitudinauy or .the mm. By sachenticipation, peak clipping is avoided and 'anysdewire with recording systems of these respective I claim as my invention:

f. 1.. A'sound re-recording system comprising a sound'. recorder having light modulating means res onsive ,to the instantaneous values of sound wa es to b'e recorded and light modulating means .'responsive .to the average value of said sound produced,` means for impressing' the lcombination waves, means for individually reproducing @plurality of separate sound records to comprise 'said lsound waves to be recorded, means for making' a recordA o fy said plurality 'of separate ysound rec ords reproduced, means forreproducing said recev ord of said pluralityof separate sound records ref- `of said sound waves being individually reproduced onsaid iirstfmentioned modulation means, and.y means for simultaneously impressing the average value ofi the reproduced Icombination.'record of said .plurality ofseparte sound .records previously recordedon said second-mentioned modu-;

lating means vto produce a combination record of 4said' pluralityofseparate records, said combina-I tion record haYng noise reduction.

- sounds from each of .said reproducers, means for mixing said .reproduced sounds, a-rst soundl lie- 2. Asound rerecording system in accordance.

with claim 1 `in which the reproduction or'said record of the combination of said sound waves previously recorded is started a vpredetermined time -interval ahead of the reproduction oisaid sound waves being recorded.

3.A sound re-recordingv system comprising' ai plurality of sound record reproducers, means for controlling the volume of reproduction or the corder for recording saidreproduced sounds without noise reduction, a second sound Arecorder forl saidreproduced sounds, means for reproducing l5, Theflight through the slitof the mask .M

is projected, on .thesound track'portionof the film` 4l by yprojection lenses 48. The noise reductionshutters 40 Iare operated by an electromag-- net 50, ied fromthe 4amplifier rectifier unit 5I which is connected to the pickup, element 5 2 of reproduceril:wheneswitch 32 is closed. Thusr with the Swiioh-)ls oiosed and the Switchs: closed. the print of the negative sound track, recorded will appear as illustrated in Fig. 3. 4

Referring now to Fig.y 3, the signal modulations are shown by the wave form 54, while the noise reduction envelope is shown at 55. Ordinarilythepoint a on the noise reduction envelope would be positioned longitudinally .of the` film recordatthe point b. However, by. advancing the noise reduction control record a predetermined amount, the "noise reduction action can -be made to anticipate thesignal record by such any amountshown by the distance between the points Il 0rd. recording a a record of saidereproduced sounds made by said rst sound recorder, and means for impressing a currentl corresponding to the average value .of the combined, reproduced sounds previously re-lv corded on the noise reduction portion of said sound Arecorder to produce a combination record of the output of said plurality of sound record reproducers having noise reduction.

4. A sound re-recording` system in accordance with claim 3 in which the volume ofreproduc tion of said plurality of records isgcontrolled automatically by, a control record of the volume variations of said plurality of records.

5. .The method of obtaining anticipatory noise y vreduction in a composite record being ref-recorded lfrom a plurality of individually reproduced records comprising'individually reproducing said plurality of records, controlling the lrelative volume of reproduction of said records, recording'a` lirstcomposite record of said individually repro-' dncedrecords, again. reproducing said plurality of records, reproducingsaid rst composite 'recsecond composite record of said plurality of records, recording a. second composite record of said plurality' of records, reproducing said first composite record'during the recording of said second. composite-record, and using the reproduction'of said first composite record .to control the noise reduction action inthe recording of said second composite record.

8. The method in accordance with claim 7 in which said noise reduction action is in advance m of the recording of said second composite record.

WALLACEV. WOLFE; 

